Patent document 1 discloses a conventional toilet flush tank. This toilet flush tank is provided below a front portion of a toilet bowl formed in a toilet main body. The toilet main body of a flush toilet provided with this toilet flush tank has a water discharge port at the lower part of the toilet bowl that is open toward a trap entrance. The toilet flush tank communicates with this discharge port. The flush toilet has a nozzle that is placed on an upstream side of the discharge port and that discharges tap water toward the discharge port. This nozzle is directly connected to a water pipe. Tap water discharged from the nozzle engulfs cleaning water stored inside the flush tank and flows into the trap entrance through the discharge port. As described, the flush toilet allows cleaning water having a flow rate (the volume of water that flows per unit time: the same applies hereinafter) that is higher than that of the tap water discharged from the nozzle to flow into the trap entrance. Therefore, the flush toilet is capable of efficiently pushing waste into a trap drainage channel.
[Patent document 1] Japanese Patent Application Publication No. 11-264173